The operation of air vehicles, such as modern fighter aircraft, often requires flight at medium to high angles of attack. Under certain conditions while flying in this operating regime, the air vehicle aerodynamic control effectiveness, especially yaw control via the rudder of the air vehicle, is significantly reduced.
The concept of using pressurized fluidic jets or pneumatic jets to control the vortex pattern shed by the nose tip of an air vehicle forebody in order to provide aerodynamic control is known in the art. Under certain circumstances, especially when an air vehicle is flown at medium to high angles of attack, the nose tip of the air vehicle produces a vortex pattern on the leeward side of the forebody of the air vehicle. This vortex pattern results in air loads on the flying surfaces of the air vehicle. Previous pneumatic vortex control efforts focused at controlling this vortex pattern in order to manipulate vortex force and moment increments for aerodynamic control of the air vehicle. These efforts resulted in designs employing jets, nozzles, piping and other hardware associated with pressurized fluid delivery at or near the nose tip of the air vehicle forebody.
These conventional pneumatic vortex control schemes, however, result in negative impacts with regard to the performance of on-board nose-mounted air vehicle sensing devices. These sensing devices include, among others, radar, forward looking infrared sensors and electro-optical sensors. These conventional scheme necessarily require that the pressurized fluid delivery hardware be located at the nose of the forebody in order to control the nose tip induced vortex pattern. As a result, the close proximity of the pressurized fluid delivery hardware, such as jets, nozzles and piping, may significantly interfere with the performance and efficiency of the nose-mounted sensing devices.
In addition, the piping and other pressurized fluid delivery hardware impact the space requirements of the nose-mounted sensing devices.
These conventional schemes also significantly impact the observability or observable signature of the air vehicle itself. The pressurized fluid delivery hardware, especially jet nozzles, potentially contribute to the radar cross-section and the infrared signature of the forebody with regard to the front aspect of the air vehicle.
Further, the pressurized fluid delivery hardware of the conventional control schemes, especially vortex control jet nozzles, must be designed so as to reduce any aerodynamic penalty.
Accordingly, there exists a need in the art for a pneumatic vortex control system which does not significantly impact the performance of nose-mounted sensing devices, the space requirements of nose-mounted sensing devices, the observable signature of the air vehicle forebody and the aerodynamic characteristics of the air vehicle forebody.